The present invention relates to a modularized power supply.
Power supplies require power processing circuitry (hereinafter xe2x80x9cpower circuitryxe2x80x9d) and control and conditioning circuitry for controlling and conditioning the power processed by the power processing circuitry. The power circuitry typically includes a transformer, a rectifier, switching elements, and power sensing elements, and is alternatively referred to herein as a xe2x80x9cpower train.xe2x80x9d The control and conditioning circuitry typically includes an input filter, a bias supply, a control section and an output filter. The power train is typically mounted on a metal base that mechanically supports and heat sinks the power circuitry. The control and conditioning circuitry is typically mounted on a circuit board that is mounted above the power train.
In some power supplies, a number of power supply modules are ganged together to provide manufacturing flexibility. For example, a 1000 watt power supply may be constructed by coupling four 250 watt power modules together. Typically, each of the modules includes the aforementioned power train and control and conditioning circuitry. Therefore, the input filter, bias supply, control section and output filter are provided for each module in addition to the power train, increasing the cost of the power supply, its size and complexity, while at the same time decreasing its reliability. Moreover, because each module or power supply unit incorporates its own control and conditioning circuitry proximate its power circuitry, heat and noise generated by the power circuitry is passed on to the control circuitry.
Another problem arises in the art of power supplies generally because the manufacturing or fabrication technology used to construct the power train generally differs from that used to construct the control and conditioning circuitry. For example, much thicker copper traces are required in the power train than are desirable for the control section of the control circuitry. Accordingly, power supply systems, including power supply modules for use in a modular power supply, have typically required an additional manufacturing process to integrate the different circuits, resulting in higher cost.
In most applications of the modularized power supply, the outputs of the modules must be synchronized to properly share the output current. In those instances, additional control is required at the system level, further increasing the size, cost and complexity of the power supply. Moreover, there are limits to the amount of control that the system can have on the modules because of the operation of the module""s own control circuits.
The present inventor is aware of a prior art xe2x80x9cboosterxe2x80x9d DC-DC converter module in which the control section is omitted. The booster operates in parallel with another DC-DC converter module that controls itself and the booster. The system addresses, to some extent, some of the problems mentioned above. However, the system does not omit the input and output filters at the booster level, so that size and manufacturing cost of the system is not reduced to the extent possible, and the system does not provide for controlling the booster modules independently, which prevents the implementation of some strategies that optimize current sharing among the boosters.
Accordingly, there is a need for a modular power supply that provides for decreased complexity, manufacturing cost and size, and increased reliability, and that provides for increased control of the modules.
The modular power supply of the present invention solves the aforementioned problems and meets the aforementioned needs by providing a plurality of power supply modules and a system control circuit for controlling the power supply modules. Each power supply module has a power circuit coupled to a power input of the module for receiving an input power current and produces an output power current at a power output of the module. The power circuits each include at least one switching element for switching the input power current or the output power current of a module The power circuits further include a control circuit input that is coupled directly to the respective said switching device. The system control circuit has a control circuit output bus for connecting to the control circuit inputs of each of the power modules and provides a respective control signal to each module for directly controlling the respective switching devices.
Preferably, the power circuits each include at least one sensing element for sensing a condition of the input power current or the respective said output power current of each module. For this purpose, the power circuits further include a control circuit output that is coupled directly to the respective sensing elements for providing a respective sense signal to said system control circuit. The system control circuit then further includes a control circuit input bus for connecting to the respective control circuit outputs of each of the power modules which directly receives the signals from the modules.
Therefore, it is a principal object of the present invention to provide a novel and improved modular power supply.
It is another object of the present invention to provide a modular power supply that provides for decreased manufacturing cost.
It is still another object of the present invention to provide a modular power supply that provides for decreased complexity.
It is yet another object of the present invention to provide a modular power supply that provides for decreased size.
It is a further object of the present invention to provide a modular power supply that provides for increased reliability.
It is still a further object of the present invention to provide a modular power supply that provides for increased control of the individual modules in the power supply.
The foregoing and other objects, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the following drawings.